Few developers are as comfortable and well-versed in how to execute winning formulas as Naughty Dog, however as much as they were already on the top of the world thanks to Crash Bandicoot and Jak and Daxter's consecutive successes, it was with Uncharted 2 that you felt the studio take a shift into truly legendary, medium-defining status. This train level in particular has been discussed by the programmers quite frequently as it's a really impressive feat of game design. The physics on the train actually move along with the geography changing alongside you, so Drake's movements and momentum are offset when going round corners for example, and although you might not be mindful of it first time through the stretch of land you cover goes in real time from one place to the other too. It's a monumental step up from other sequences like this set aboard moving vehicles and platforms (like Pandora Tomorrow's from earlier) that usually feature one background repeated over and over, and a truly amazing level that gets better every time you play it.
